> The continuing heatwave around the world has highlighted the health risks of prolonged exposure to air pollution and ultraviolet radiation
> While the ozone layer in the upper atmosphere shields the earth from the ultraviolet rays contained in sunlight,ozone that forms near the ground is a health hazard
> Ultraviolet (UV) radiation:
UVA...most abundant source of solar radiation,can damage human tissue and increase the risk of developing skin cancer
UVB...less abundant than UVA as large amount is absorbed by ozone layer.Penetrates skin less deeply but still damaging.
UVC...very hazardous to skin but is completely absorbed by ozone layer.
> Ground-level ozone is formed by a chemical reaction between air pollutants (volatile organic compuond and oxides of nitrogen) and sunlight.
> How air pollution affects health:
--Ground-level ozone irritates eyes,causes headaches and allergies such as asthma.
--Hydrocarbons can irritates eyes,cause coughing and lead to lung cancer.Can also affect people with heart disease.
--Nitrogen dioxide attacks certain immune cells and provoke bacterial and viral infections,causing drowsiness,vertigo and vomiting.
--Sulphur dioxide attacks nose,throat and lungs.Long-term exposure can cause respiratory illness
--Particulate matter can cause coughing,painful breathing and aggravate asthma.Can accumulate in respiratory system.
> Sunscreens protect skin from UV rays and are classified by Sun Protection Factor (SPF):eg SPF 30 ...97% protection.,SPF 15....93% protection.,SPF 4...75% protection.
> Ozone air quality index:
0-50.....GOOD
51-100....MODERATE
101-150....UNHEALTHY FOR SENSITIVE GROUPS
151-200....UNHEALTHY
201-300....VERY UNHEALTHY
301-500....HAZARDOUS./
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