Qualité de l’air à Osasco

Is Osasco a very polluted city right now?

Osasco is a municipality in São Paulo State, Brazil, located in the Greater São Paulo and ranking 5^th in population among São Paulo municipalities.

According to a census conducted in 2020, Osasco had an estimated population of approximately 700,000 people. They reside in a relatively small area of 65 square kilometres which gives it a density similar to Tokyo and New York.

Towards the end of 2021, Osasco was experiencing a period of “Moderate” quality air with a US AQI reading of 53. This United States Air Quality Index number is calculated using the levels of six of the most commonly occurring air pollutants, such as nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide and both sizes of particulate matter, which are PM2.5 and PM10. It can then be used as the metric when comparing air quality in other cities around the world. If data is unavailable for all 6 pollutants, a figure can still be calculated by using what figures there are. Five of these pollutants were measured and recorded in Osasco. They were; PM2.5 - 13 µg/m³, PM10 - 11 µg/m³, nitrogen dioxide (NO₂) - 46 µg/m³, sulphur dioxide (SO₂) - 1 µg/m³ and carbon monoxide (CO) - 801.5 µg/m³. These figures are measured in microns per cubic metre.

This level of PM2.5 is just below one 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 the level of air pollution is classified as “Moderate”, the proffered advice would be to remain indoors as much as possible, closing all doors and windows to prevent more polluted air from entering the rooms. Those of a sensitive disposition should limit their time spent outside and should always wear a good quality face mask when doing so. For up-to-date information about air quality, there is an app available from AirVisual which is downloadable for all mobile devices. This will give you the air quality in real-time.

Does the level of air pollution vary much throughout the year in Osasco?

Air quality is very volatile as it is subject to many external influencing factors such as meteorological and atmospheric changes.

Looking back at the figures for 2020, published by IQAir.com, it can be seen that the month with the cleanest air was December when the level was classified as being “Good” with a reading of 11.7 µg/m³. The remaining eleven months of the year returned figures from the “Moderate” classification between 12.1 and 35.4 µg/m³. Out of these months, the cleanest was March with a figure of 12.5 µg/m³. The worst quality was found in September when the reading was 25.6 µg/m³.

Historically, records were first kept in 2018 when the recorded figure was 22.1 µg/m³. An improvement was seen the following year when the figure was 19.8 µg/m³. In 2020 another improvement was seen when the figure was 15.7 µg/m³, however, this reading may have been affected by the COVID-19 pandemic as many vehicles were no longer in daily use because the offices were closed, 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 it on a temporary basis.

What is the chief source of polluted air in Osasco?

Osasco is among the first three cities with the worst index, probably due to the large number of vehicles on the road and the presence of industries. PM2.5 (fine particulate material) is a fine dust emitted mainly by vehicles, industries and sugarcane burning.

With the quarantine since 24^th March, as a way to contain COVID-19, the atmospheric pollution rates in the city were reduced by about 50 per cent in just one week. This cleaner sky that can be noticed at the beginning of the quarantine is a result of the reduction in the circulation of vehicles, the main source of pollutant emissions in the city. As a large part of them stopped circulating, it is clear the decrease of primary pollutants such as carbon monoxide, emitted mainly by cars and nitrogen oxides, emitted mainly by diesel vehicles, which can be confirmed in atmospheric data.

In addition to the significant reduction in primary pollutants, directly linked to vehicular emissions, there was also a decrease of about 30 per cent in inhalable particulate matter. These are pollutants PM10, particulate material with a diameter of up to 10 micrometres, related to the action of vehicles that resuspend the dust from the ground, and PM2.5, with up to 2.5 micrometres, formed by secondary processes from the burning of fuel.

What can be done to improve air quality in Osasco?

All drivers will have to take their car to measure the number of pollutants released by the exhaust and released into the environment. The inspection will follow the schedule adopted by the licensing. Whoever has a car with an emission above the allowed limit will have up to 30 days to regulate the engine, otherwise they will receive a fine. Those who pass the test will have a seal glued to the glass by the company responsible for the service and will be free to circulate on the streets and carry out the next license.

What are the health impacts of breathing dirty air in Osasco?

Breathing frequency and depth typically increase during physical activity and at high altitudes, but this increase is unlikely to cause discomfort. The respiratory rate increases even during rest in people with various disorders, whether in the lungs or in other parts of the body. For example, people with a fever usually breathe more quickly.

In dyspnoea, rapid breathing is accompanied by a feeling of shortness of breath. People feel unable to breathe with the necessary depth and speed. They may notice that expanding the chest during inspiration or expiration requires more effort than usual. They may also have the unpleasant feeling that inspiration is urgently needed before the expiration is complete, and they have various sensations, usually described as tightness in the chest.