Air quality in Sao Caetano do Sul

What is the current level of air pollution in São Caetano do Sul?

São Caetano do Sul is a city in São Paulo state in Brazil and is part of the Metropolitan Region of São Paulo. A census was conducted in 2020 which estimated the population to be approximately 162,000 residents although there are no real boundaries between the different areas within the conurbation. It is intensely conurbated with São Paulo, Santo André and São Bernardo do Campo, causing the physical limits between cities to be lost.

At the beginning of 2022, São Caetano do Sul was experiencing a period of “Moderate” air quality with a US AQI reading of 74. This United States Air Quality Index number is an internationally used set of metrics supported by the World Health Organisation (WHO) and is used to compare the air quality in different cities throughout the world using comparable standards. It is calculated by using the levels of the six most commonly found pollutants such as nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide and both sizes of particulate matter, which are PM2.5 and PM10. If all six figures are not always available in which case, a level is calculated by using what data there is. In this case, all six pollutants were measured and recorded. The results were as follows; PM2.5 - 23 µg/m³, PM10 - 32 µg/m³, ozone (O₃) - 26 µg/m³, nitrogen dioxide (NO₂) - 27 µg/m³, sulphur dioxide (SO₂) - 1 µg/m³ and carbon monoxide (CO) - 458 µg/m³.

This level of PM2.5 is just over four and a half times above the recommended safe level of 10 µg/m³ as suggested by the World Health Organisation (WHO) as being an acceptable level. Although no amount of air pollution is considered to be safe.

When air pollution is classified as being “Moderate” the given advice would be to remain indoors as much as possible, closing doors and windows to prevent the ingress of more polluted air. Those who are more sensitive to poor quality air should avoid venturing outside until it improves. If this is unavoidable, then a good quality face mask should be worn at all times. All types of outdoor exercise should be avoided until the air quality improves. There is a downloadable app from AirVisual.com which is suitable for all operating systems and gives the latest information regarding air quality in real-time.

Does the level of air pollution remain the same throughout the year in São Caetano do Sul?

Looking back at the figures for 2020, published by IQAir.com, it can readily be seen that the months of February and December achieved less than the target figure as recommended by the WHO. To make this achievement the reading needs to be less than 10 µg/m³. The respective figures were 9.9 and 10.0 µg/m³. The month of January saw “Good” air quality with a reading of 12 µg/m³. The remaining nine months of the year saw air quality from the “Moderate” group with figures between 12.1 and 35.4 µg/m³. The month with the dirtiest air was September with a reading of 23.5 µg/m³.

Records pertaining to air pollution were first kept in 2018 when a figure of 18.1 µg/m³ was recorded. The following year, a figure of 17.2 µg/m³ was noted and in 2020 the figure was 15 µg/m³.

This low figure was almost expected because it will have been affected by the COVID-19 pandemic as many vehicles were no longer in daily use because the offices were closed and the staff encouraged to work from home, in an attempt to halt the spread of the virus. Many factories and non-essential production units were also required to close which removed their emissions from the atmosphere, albeit on a temporary basis. Worldwide, cities reported a much better quality of air due to the general lack of traffic pollution in city centres due to the pandemic.

Is there a main source of air pollution in São Caetano do Sul?

Hydrocarbons (HC) are in the form of gases, fine particles or drops, these compounds are divided into total hydrocarbons, simple hydrocarbons such as methane and non-methane hydrocarbons. Motorcycles are major emitters of HC, followed by heavy vehicles, cars, solvent operations and even painting.

For more than ten years, the recommendations of the World Health Organisation (WHO) report that air pollution is predominantly concentrated in four pollutants, which encompass particulate matter, ozone, nitrogen dioxide and sulphur dioxide in all regions. According to studies, inhalable particulate matter (PM 10) and fine inhalable particulate matter (PM2.5) are residues from the burning of fossil fuels and include diesel oil, gasoline, natural gas and mineral coal.

What can be done to improve air quality in São Caetano do Sul?

There are numerous corrective and preventive tips to try to alleviate this problem, including:

• Stipulating limits on pollution levels in urban and rural environments.
• Strict criteria regarding gas emission standards.
• Periodic monitoring of polluting sources.
• Encourage the use of less polluting technologies.
• Use of equipment that reduces the levels of emitted gases, among which we can mention: automotive catalytic converters, depollution filters in industrial chimneys, amongst others.
• Constantly monitor places where solid waste is deposited, so that there are no fires.
• Promote the reforestation of degraded areas.
• Elaboration of preventive projects against possible atmospheric pollution of great proportion.
• Control fires (crops, pastures and forests).
• Avoid the use of pesticides, giving preference to biological control.
• Preservation of natural forests.
• Implementation of a quality public transport system.
• Creation and expansion of green areas in urban areas, such as tree-lined squares, ecological parks, gardens, etc.

What are the detrimental effects of breathing polluted air?

The amount of air pollution depends on the number of emitting sources (many vehicles and industries, use of firewood and gas in the kitchen), the relief and the climate of the city. Places with little wind and rain or that are surrounded by hills tend to be more polluted. In winter, pollution gets worse, because the cold makes it difficult for it to move away from the ground.

People who live in areas with very dirty air may experience symptoms that are easy to notice, such as a dry throat and mouth, shortness of breath and coughing which is the body's attempt to flush out intruders that enter through the respiratory system. Other signs are silent: increased risk of heart attack, obesity, memory impairment and even impact on fertility.

The so-called particulate materials are the main responsible for attacking our health. They are the ones who smear the facades of buildings with ash. In the body, they enter through the nostrils to the lungs and, from there, they spread through the bloodstream and the entire body – even reaching the brain.