All-causeFootnote 1 death and DALY attributable to air pollution

Figure 2 illustrates the impact of air pollution on health, in terms of deaths and DALYs, in BRICS from 1990 to 2019. The global death toll due to air pollution was 66.72 million in 2019, which was a 3% increase from 65.01 million in 1990. In India, the number of deaths due to air pollution was 15.41 million in 2019, which was a considerable increase of over 15% from 13.33 million in 1990. On the other hand, deaths caused by air pollution in China declined slightly by 2.63% from 18.96 million in 1990 to 18.48 million in 2019. Brazil, the Russian Federation, and South Africa had much lower death rates due to air pollution compared to China and India. In addition, Fig. 2 compares the DALY trends globally with the BRICS countries. It shows that the number of DALYs worldwide declined from 2807.18 million in 1990 to 2132.85 million in 2019. The same trend was also observed in the BRICS countries.

Fig. 2

Source: Author’s estimation from the GBD-2019 Survey data (IHME 2020)

All causes of Death and DALYs number in millions (all ages) attributable to air pollution in Global and BRICS (1990–2019). Note: All causes of Death and DALYs rate (all ages) attributable to air pollution in Global and BRICS are reported in the Appendix Fig. 3.

In the appendix, Fig. 5 shows the trends of global death rates and DALY rates caused by air pollution over the years. The data reveals that the death rate declined from 122 to 86 per 100,000 persons worldwide between 1990 and 2019. Similarly, China and India also witnessed a decline in death rates due to air pollution from 160 and 156 in 1990 to 130 and 120 in 2019, respectively. This trend is also observed in other BRICS countries. Additionally, Figure 5 presents the DALY rates of both global and BRICS countries, which also saw a decline from 5247 persons in 1990 to 2757 in 2019. The declining trend of air pollution risk towards human health can be attributed to several factors at the global and BRICS levels, including CO2 emissions per capita, PM2.5 air pollution exposure, renewable energy consumption, and fossil fuel energy consumption (See Figure 6 and 7. Despite Brazil having higher levels of CO2 emissions per capita and PM2.5 air pollution exposure, their death and DALY rates remain much lower compared to India and China. However, it is essential to adopt clean energy and healthcare facilities to minimize the adverse effects of air pollution on human health.

Communicable and non-communicable diseases attributable to air pollution

The presented data in Table 1 highlights the impact of air pollution on communicable and non-communicable diseases (CDs and NCDs) globally and in BRICS countries. Air pollution was divided into three minor components, namely ambient particulate matter pollution, household air pollution from solid fuels, and ambient ozone pollution. In 2019, the global death toll due to CDs and NCDs caused by air pollution was 11.36 million and 55.36 million respectively. In India, the deaths due to air pollution in case of CDs and NCDs were 2.76 million and 13.91 million persons respectively in 2019. Similarly, in China, the figures were 0.53 million and 17.95 million persons respectively during the same period. The data in Table 1 also shows that the BRICS countries have experienced a transition from CDs to NCDs, with CDs dominating in 1990, especially in China and India. However, their prevalence has not decreased over the years. The major contributor to NCDs is ambient particulate matter pollution, which resulted in 8.25 million and 13.82 million deaths in various NCDs in 2019 in India and China respectively. We also found that ambient ozone pollution does not cause any communicable diseases, rather it affects NCDs related deaths, which was around 3.65 million at the global level in 2019.

Table 1 Death and DALYs number in millions (all ages) attributable to air pollution of communicable and non-communicable diseases in Global and BRICS (1990–2019)

In Table 1, you can find the DALY numbers caused by air pollution for CDs and NCDs. The data shows that the DALYs have increased for NCDs while they have decreased for CDs globally, as well as in BRICS. In 1990, the global DALY number for CDs was 1688.89 million, and by 2019, it decreased to 720.50 million. Whereas, in 1990, the global DALY number for NCDs was 1118.29 million, and by 2019, it decreased to 1412.34 million. Similar results were noticed in the case of air pollution's minor risk factors in BRICS countries. You can also find death and DALYs rates of people affected by CDs and NCDs due to air pollution in Appendix Table 4. The table presents data for global and BRICS country contexts between 1990 and 2019. According to the table, in 2019, the CDs death rate was 15 (CI:12–18), and the DALYs rate was 931 (CI: 761–1130) at the global level. Whereas, the NCDs death rate was 72 (CI: 63–80), and the DALYs rate was 1825 (CI: 1611–2030) in 2019. The trend of increasing NCDs as compared to CDs has been seen in most of the BRICS countries.

Air pollution has evolved in its impact on health, initially affecting communicable diseases (CDs) more prominently but now increasingly affecting Non-communicable diseases (NCDs) (Guan et al. 2016). Recent research highlights this shift, emphasizing the growing influence of air pollution on NCDs compared to previous decades. In BRICS countries, air pollution significantly contributes to NCD-related deaths, with ambient particulate matter pollution and household air pollution from solid fuels being major contributors. Globally, ambient particulate matter pollution caused approximately 37 million deaths in 2019, while household air pollution resulted in about 16.44 million NCD-related deaths during the same period. Notably, India and China bear the highest burden of NCD-related deaths attributed to ambient ozone pollution, indicating a pressing need for mitigation efforts in these regions (See Table 1 and Appendix Table 4). These findings underscore the substantial public health burden posed by air pollution, particularly in China and India, underscoring the urgency for effective mitigation strategies.

A significant observation is the decline in the contribution of household air pollution from solid fuels to non-communicable disease (NCD)-related deaths and disability-adjusted life years (DALYs) globally and within BRICS countries between 1990 and 2019. Notably, in China, the number of NCD-related deaths attributed to household solid fuels decreased from 10.97 million in 1990 to 3.51 million in 2019 (See Table 1 and Appendix Table 4). Conversely, the prevalence of NCD-related deaths and DALYs due to ambient particulate matter pollution remains a critical issue across almost all BRICS countries, posing a substantial risk to global health.

Gender-wise health effects of air pollution

In Fig 3, we can see the impact of air pollution on the health of males and females in the BRICS countries and globally between 1990 and 2019. The health effects are measured by the number of deaths and DALYs (disability-adjusted life years) per 100,000 population, for communicable diseases (CDs) and non-communicable diseases (NCDs). The figure shows that males have a higher death rate in both CDs and NCDs compared to females, both in the BRICS countries and globally. The same trend is observed in DALYs rates. Among the BRICS countries, China has the highest number of NCD-related deaths and DALYs, followed by India.

Fig. 3

Source: Author’s estimation from the GBD-2019 Survey data (IHME 2020)

Gender-wise Death and DALY rates (per 100,000 population) for all ages attributable to air pollution.

The data presented in Fig 3 suggests that males bear a greater burden of ambient particulate matter pollution, likely due to their increased exposure to outdoor environments. In contrast, females, who predominantly spend more time indoors, appear to be less vulnerable. This discrepancy may be attributed to the reduction in household air pollution from solid fuels over time, potentially rendering females less susceptible to air pollution compared to males (Murray et al. 2020).

Age-wise health effects of air pollution risk factors

The impact of air pollution on human health across different age groups is shown in Fig. 4a–f. The study divides age groups into sub-groups such as under-5 years, 5–14 years, 15–49 years, 50–69 years, and 70+ years. Fig. 4 a shows the death and DALYs rates for different age groups globally. It indicates that indoor air pollution was the primary risk factor for deaths and DALYs in the 1990s, followed by ambient particulate matter and ambient ozone pollution.

Fig. 4

Source: Author’s estimation from the GBD-2019 Survey data (IHME 2020)

a Age-wise total death and DALYs rate attributable air pollution risk factors in Global. b Age-wise total death and DALYs rate attributable air pollution risk factors in Brazil. c Age-wise total death and DALYs rate attributable air pollution risk factors in Russia. d Age-wise total death and DALYs rate attributable air pollution risk factors in India. e Age-wise total death and DALYs rate attributable air pollution risk factors in China. f Age-wise total death and DALYs rate attributable air pollution risk factors in South Africa.

The impact of air pollution on different age groups in the 1990s showed that it was more severe in the 50–69 years and 70+ years age groups, followed by children under 5 years. However, the effects were less severe among the age group 5–14 years and 15–69 years. Our study shows that the impact of air pollution on human health follows a 'U' shaped curve, initially affecting the under-5 year age group, and then becoming more severe among older age populations. This finding was consistent across China, Russia, India, and South Africa. The effects of ambient ozone pollution were negligible in the 1990s, but its impact on population deaths and DALYs had increased in the 70+ year population in China, Russia, and India. As compared to the 1990 GBD study, the effects of air pollution were mostly impacting the population above 50 years in the 2019 GBD estimations. Our study, like that of Saldiva et al. (1995a, b), found a strong link between higher levels of particulate matter in the air and increased mortality rates among the elderly. This highlights the urgent need to tackle air pollution to safeguard vulnerable groups such as the elderly from adverse health effects.

Disease-wise health effects of air pollution on global deaths

Table 2 displays the number of deaths that can be attributed to air pollution in the cases of various communicable diseases (CDs) and non-communicable diseases (NCDs) in both the global and BRICS country contexts. Our findings indicate that air pollution, in the form of ambient particulate matter pollution and household pollution from solid fuels, contributed to the occurrence of five communicable diseases, namely diarrhea, meningitis, encephalitis, neonatal disorders, respiratory infections, and tuberculosis. In addition, six non-communicable diseases were found to be linked to air pollution, including Tracheal, bronchus, and lung cancer, ischemic heart disease, stroke, chronic obstructive pulmonary disease, diabetes mellitus type 2, and chronic obstructive pulmonary disease.

Table 2 Death number in millions (all ages) attributable to air pollution on various communicable and non-communicable diseases in Global and BRICS (1990–2019)

The data reveals that globally, respiratory infections and tuberculosis were responsible for the highest number of deaths (15.05 million) followed by chronic obstructive pulmonary disease (14.92 million), stroke (13.79 million), and ischemic heart disease (12.25 million) in the 1990s. However, there has been a shift towards a rising number of deaths due to non-communicable diseases, such as ischemic heart disease (18.43 million), stroke (17.02 million), and chronic obstructive pulmonary disease (14.59 million) in 2019. Hence, our analysis suggests that there has been an epidemiological transition from communicable diseases (CDs) to non-communicable diseases (NCDs) at a global level. This conclusion has been supported by several country-level studies (Zhou et al. 2019; Quigley 2006; Adogu et al., 2015).

Air pollution has a significant impact on public health in the BRICS countries, with different diseases affected in different ways. In China, for instance, stroke (6.79 million) and chronic obstructive pulmonary disease (4.36 million) were the leading causes of death in 2019. Non-communicable diseases (NCDs) such as tracheal, bronchus, and lung cancer; ischemic heart disease; stroke; and type 2 diabetes have increased since the 1990s. Meanwhile, in Brazil, cardiovascular diseases such as ischemic heart disease (0.22 million) and stroke (0.24 million) were the top causes of death in the 1990s, but these have declined in 2019. However, in India, the burden of disease due to air pollution has increased in 2019 compared to the 1990s. Respiratory infection and tuberculosis (3.79 million) were the leading causes of death in the 1990s, followed by pulmonary disease (3.41 million), but in 2019, pulmonary disease (6.29 million) was the top contributor, followed by ischemic heart disease (4.87 million) and stroke-related cardiovascular diseases (2.71 million). Similar trends were observed in South Africa, where cardiovascular diseases have declined, but new types of NCDs have emerged, including type 2 diabetes (0.05 million), pulmonary disease (0.03 million), and tracheal, bronchus, and lung cancer (0.02 million), due to air pollution.

It has been discovered that two contagious diseases caused by air pollution were widespread in the global disease burden during the 1990s. These diseases are neonatal disorders which accounted for 6.04 million cases, and respiratory infections and tuberculosis, which accounted for 15.05 million cases. The major contributor to these diseases in 1990 was household air pollution from solid fuels, but this contribution has decreased since then. In 2019, air pollution was responsible for 7.49 million deaths due to respiratory infections and tuberculosis, and 3.73 million deaths due to neonatal disorders, globally. In India alone, air pollution caused around 1.86 million deaths due to respiratory infections and tuberculosis in 2019. There has been a substantial reduction in deaths caused by many communicable diseases, particularly those originating from household air pollution, since 1990. However, ambient particulate matter pollution remains a significant risk factor for many non-communicable diseases globally, including in BRICS. Several NCDs have emerged as a significant source of the global burden of disease, such as Ischemic heart, Tracheal, bronchus, and lung cancer, Stroke, Chronic obstructive pulmonary, and Diabetes mellitus type 2.

Disease-wise health effects of air pollution on Global DALYs

Table 3 provides a comparative analysis of the disease-wise total numbers of disability-adjusted life years (DALYs) attributable to air pollution for all age groups in the world and the BRICS countries. It is observed that the overall number of DALYs due to communicable diseases (CDs) such as respiratory infections and tuberculosis have decreased globally in 2019 as compared to the 1990s. Neonatal disorders also showed a decline (331 million). However, the numbers for non-communicable diseases (NCDs) such as type 2 diabetes mellitus (129 million), ischemic heart disease (453 million), and stroke (434 million) have increased.

Table 3 DALYs numbers in millions (all ages) attributable to air pollution of various communicable and non-communicable diseases in Global and BRICS (1990–2019)

Similar trends were observed for other countries as well, where DALY numbers increased for various NCDs. For instance, the DALY numbers of Tracheal, bronchus, and lung cancer (7.14 million), stroke (73 million), Chronic obstructive pulmonary disease (137. million), and type 2 diabetes mellitus (29 million) increased in India in 2019 as compared to 1990. China also showed similar trends. However, the DALY numbers of many NCDs had declined in Brazil and Russia in 2019 as compared to 1990, such as stroke and ischemic heart disease, while type 2 diabetes mellitus increased in 2019.

It is found that ambient ozone pollution and ambient particulate matter pollution are the primary contributors to the burden of diseases at the global level as well as in BRICS countries. In 2019, many NCDs were caused by these two risk factors, resulting in deaths and DALYs. In 1990, household air pollution was considered a major risk factor, followed by ambient ozone pollution and ambient particulate matter pollution, leading to more deaths and DALYs due to CDs.

It is observed that the DALY numbers for two major communicable diseases, namely Neonatal disorders, Respiratory infections, and tuberculosis, have increased globally from 1990 to 2019 due to ambient particulate matter pollution. However, the effects of solid fuels from households on these two diseases have declined globally, including India and South Africa.

Almost all NCDs originating from ambient matter pollution have increased globally from 1990 to 2019, including the BRICS countries. According to the GBD data, cataract, a disease leading to blindness and vision loss, has increased in 2019 due to household air pollution from solid fuels.