It is a pity that Mumbai's air pollution is threatening the cities growing importance as a player on the global economic stage. Industrial emissions, the burning of refuse and vehicle exhausts are combining to produce unacceptably high levels of nitrogen oxides and particulate matter (PM) in Mumbai's air. The population of the city has grown dramatically in recent years, and has now reached 18 million – the fourth highest in the world and the most densely populated. The World Health Organization (WHO) urban air pollution database finds that average levels of PM10 pollution in Mumbai is 132 micrograms per cubic metre.  Eventhough Mumbai's air is very polluted, it is far from being the most polluted city in the world. That dubious distinction goes to the city of Ahwaz in Iran,

In a new study published in Environmental Health Perspectives, Chinese researchers shed light on which components of PM2.5 pollution do most damage to health. Previous work has shown that exposure to PM2.5s (particles less than 2.5 microns in size) are linked to heart and lung problems and to excess mortality.  But it has not been known just what compounds in the PM2.5s do the most damage. 

China has one of the highest concentrations of PM2.5 pollution in the world, but the impact that air pollution exposures have on the health of the Chinese population is not well understood.  A team led by Haidong Kan of Fudan University in Shanghai studied PM2.5 pollution in Xi’an, which is one of China’s most polluted cities. It is the largest city in northwestern China and has a

The importance of PM2.5 air pollution was finally been recognised when the Department of Environment, Food and Rural Affair (Defra) launched its new Daily Air Quality Index (DAQI)  early this year.  Previously, the index had not changed for 12 years. Defra took advice from the Committee on the Medical Effects of Air Pollution when redesigning the index. 

There are coloured index bands for each of the key pollutants, namely:

• Nitrogen dioxide
• Sulphur dioxide
• Ozone
• PM10s (particles of size 10 microns or less)
• PM2.5s (particles of size 2.5 microns or less).

Levels of pollution are classed from 1-10, depending on the level measured. Levels 1-3 are classed 'low', 4-6 'moderate', 7-9 'high' and 10 'very high'. Each index band is linked to advice for both healthy people and those with asthma and other lung

Indoor air quality is an often overlooked source of exposure to pollution that can cause ill health. Far more attention is given to outdoor pollution. In fact, indoor air pollution may cause nearly 3% of the total global burden of disease, according to the World Health Organization.  It makes sense – after all many of us spend up to 90% of our time indoors. 

Cooking, either with solid fuel or gas, can be a major source of indoor air pollution, alongside cigarette smoke and fumes emitted from furniture, DIY products and office equipment. A new study from Spain shows how cooking with gas at home during pregnancy is linked with problems with infant brain development. The work was reported in the journal Epidemiology and described in Environmental Health News.

Babies born

After a number of scandals, it looks as if the government in Beijing has finally woken up to the fact that the city's air pollution is posing a serious problem to those living there, including those relocating from abroad for business reasons. 

State media outlets have said that Beijing will act to reduce air pollution levels by 15 per cent by 2015 and by as much as 30 per cent by 2020. They'll achieve this by phasing out the older, more polluting cars, closing down or relocating dirty factories, like cement works which emit a lot of dust, and they will also plant many new forests. 

Citizens of Beijing have been calling for this type of action for some time now. Beijing's pollution is the very visible kind – it is so bad that the airport had to be closed owing to lack of visibility. Cancelled flights are, of course, bad for business. But worse still is the impact of breathing in air pollution on your lungs.

Why not kick off 2012 with a resolution to improve the quality of your indoor air? Poor indoor air quality is associated with a number of health problems, such as asthma and other allergies, multiple chemical sensitivity, respiratory and heart disease, and lung cancer. We spend most of our time indoors, at home, at school or in the workplace, and are exposed to a wide range of pollutants including allergens, volatile organic compounds, and nitrogen dioxide. Trying out our Top Tips will be a very worthwhile investment in terms of your, and your family's, health. 

1. Ventilation. This is a very important thing you can do to improve the quality of air in your home if airborne contamination originated from within your home, and the outside air in the area where you live is relatively clean. So, when did you last open a window? Get into the habit of opening several

Did you know that as many people (4,000) died from air pollution in London in 2008 as died in the Great Smog of 1952? That is the conclusion reached by the Environmental Audit Committee (EAC) in 'Air Quality: A follow up report.' Therefore, only smoking causes more premature deaths. In 1952, it was short-term exposure to heavy air pollution that caused the deaths. Today's air pollution deaths come from long-term exposure to PM_2.5  pollution which consists of tiny soot particles coated with organic compounds that are inhaled deep into the lungs.

The EAC's inquiry was undertaken to assess how far government had implemented processes outlined in its November 2010 response to an earlier report. They slam government for failure to act on what is seen as a major public health crisis and single out London Mayor Boris Johnson for his failure to achieve acceptable air quality in London (which we must now call 'The Olympic City'). 

Simon Birkett,