Air Quality Standards and Extreme Ozone Events in the São Paulo Megacity

Abstract

Ozone events in South America might be triggered by increasing air temperatures and dry conditions, leading to vulnerable population exposure. The current air quality standards and attention levels in São Paulo state, Brazil, are 40% higher and 25% higher, respectively, than the limits recommended by the World Health Organization (WHO). We simulated an extreme ozone event in the São Paulo megacity using the Weather Research and Forecast/Chemistry model during an extreme event characterized by positive anomalies of air temperature and solar radiation. Results were evaluated using the different air quality limits from São Paulo state and the WHO, also with socioeconomic vulnerability data from the Brazilian census and cost analysis for the public health system from the extreme episode. More than 3 million people in vulnerability conditions, such as low income and families with an above-average percentage of children, live in areas where ozone concentrations exceeded the attention levels of the WHO during the episode, which is ignored by the lenient SP state environmental laws. WHO air quality guidelines must be adopted urgently in developing nations in order to provide a more accurate basis for cost analysis and population exposure, particularly the for vulnerable population groups.

Concurrent Heat Waves and Extreme Ozone (O3) Episodes: Combined Atmospheric Patterns and Impact on Human Health

“…According to the study by Chiquetto and colleagues, the previously mentioned reactions may occur when higher air temperatures exceed 20 °C; the highest O 3 mixing ratios appear under the warmest conditions [ 4 ]. Consequently, both NO x emissions (the precursor) and the meteorological state control ambient O 3 concentration.…”

Atmospheric effects of air pollution during dry and wet periods in São Paulo

“…The biggest cosmopolitan and financial region is located in Southeast Brazil and is formed by the agglomeration of São Paulo city and its surrounding areas that include coastal cities as well. These cities suffer high levels of air pollutants from anthropogenic activities, with on-road vehicles being the main source over metropolitan areas (23)(24)(25). The weather and climate over the Southeast Brazil suffer the direct influence of meteorological systems from tropical, subtropical, and extratropical genesis (26,27), closely linked to low-frequency variability in interseason (28), interannual (29,30), and interdecadal (31,32) timescales.…”

“…These cities suffer high levels of air pollutants from anthropogenic activities, with on-road vehicles being the main source in metropolitan areas. [23][24][25] The weather and climate of Southeast Brazil suffer the direct inuence of meteorological systems from tropical, subtropical, and extratropical genesis, 26,27 closely linked to low-frequency variability in interseason, 28 interannual, 29,30 and interdecadal 31,32 timescales. Meteorological systems can promote the dispersion of air pollutants or trap them.…”

Air pollution and its impact on the concentration of airborne fungi in the megacity of São Paulo, Brazil

“…Along the year, those pollutants reach higher values than the ones preconized by the national and the WHO air quality standards (Siciliano et al, 2020;Chiquetto et al, 2019;Abe and Miraglia, 2016). Some local policies were stablished willing to reduce those values and minimize the health impact, such as traffic restrictions of heavy vehicles and rotation for light vehicles in the city (Carvalho et al, 2015;Andrade et al, 2017).…”