Air pollution kills!
The World Health Organisation (WHO) flags air pollution as the largest environmental health risk in the world.
Two decades of research have shown that air pollution can trigger heart attacks, strokes, and irregular heart rhythms, particularly in people already at risk for these conditions.
In its report released in March 2014, WHO estimated that about 7 million people worldwide died as a result of air pollution exposure in 2012 alone. South-East Asia and Western Pacific areas of the world are the regions in which health is most affected by air pollution, with some 3.3 million deaths linked to indoor air pollution in 2012 and 2.6 million to outdoor air pollution – scarily more deaths from polluted air indoors than outdoors!
We carried a previous article on: Air indoors more polluted than outdoors .
According to WHO, indoor air pollution-related deaths in 2012 were a result of stroke (34%), ischemic heart disease (26%), chronic obstructive pulmonary disease (COPD) (22%), acute respiratory infections in children (12%), and lung cancer (6%).
The current on-off haze crisis is naturally of grave concern. The key air pollutants of haze include particulate matter (PM) or particulates, sulphur dioxide, ozone, nitrogen dioxide and carbon monoxide. Even short-term exposure (i.e. continuous exposure to unhealthy daily average PSI levels over a few days) can cause respiratory symptoms and aggravate existing heart or lung disease. Exposure may also cause irritation of the eyes, nose and throat in healthy individuals.
Particulates are the deadliest forms of air pollution due to their ability to penetrate deep into the lungs and blood streams unfiltered, causing permanent DNA mutations, heart attacks, and premature death. There are two size main classes of particulates – PM10 (up to 10 microns) and PM2.5 (up to 2.5 microns). How small is a micron? One micron is 1,000 times smaller than a millimetre! The smaller PM2.5 particles are far more harmful as they stay in the air longer and convey further, and penetrate deeper into the lungs. While rain can wash away the PM10 particles in the air partially, it does not do much to PM2.5. Exposure to PM2.5 can lead to significantly increased mortality as well as greater cancer risks.
And like all outdoor air pollution, the particulates easily penetrate indoors, mixing with the other indoor air pollutants, such as dust. Visible dust is about 10 microns in diameter. The type of dust that can lodge in your lungs is more commonly about .3 micron, invisible to the naked eye.
“Dust”, which is the catchall term for the minute residue shed by the building and its occupants (including pets and pests), is present even in the cleanest homes. It is not just bothersome and potentially embarrassing when you have guests, it can also be a serious pollutant, particularly for allergy sufferers, asthmatics and those hypersensitive to airborne particulates. Even for people not suffering from these conditions, breathing air laden with bacteria and other contaminants could lead to symptoms such as sneezing, watery eyes, coughing, shortness of breath, dizziness, lethargy, fever, and even digestive problems!
Millions of people suffer year-round from allergy symptoms caused by indoor allergens. The main culprits include dust mite droppings, animal dander (skin flakes from an animal’s hair or fur), cockroach droppings and moulds.
Sensitivity to dust mites is often overlooked. Diagnostic tests and clinical studies by allergists have shown house dust mite to be the most common allergy in asthmatics, and an important “root cause” for the development of asthma in young children. Recent studies suggest that at least 45% of young people with asthma are allergic to house dust mites. Unlike “seasonal” allergies caused by moulds and pollen, people who are allergic to dust mites often will have symptoms year round. Dust mites can literally make you feel like you are having an endless cold!
Evidence shows that some episodes of nonspecific symptoms known as "sick building syndrome" may be related to microbial contamination in buildings.
Meanwhile, some volatile organic compounds (VOCs) present in indoor air have been shown to cause cancer in animals exposed to high concentrations. A few of these VOCs — e.g. formaldehyde and benzene — are considered by many authorities to be proven or probable human carcinogens (i.e. cancer causing).
Studies by the United States Environmental Protection Agency’s (EPA) found concentrations of many VOCs consistently higher indoors than outdoors.
EPA-supported Indoor Air Quality Scientific Findings Resource Bank (IAQ-SFRB) highlights four substantial review articles associating high VOC concentrations in indoor air with allergies, asthma, and related respiratory symptoms. Given that indoor VOCs may significantly increase the risks of cancer, it is useful know which indoor sources of VOCs pose the greatest risk (see table below).
| VOC | Examples of Indoor Sources |
|---|---|
| formaldehyde | some manufactured wood products used as building materials and in furniture; tobacco smoke; chemical reactions with common indoor VOCs; unvented combustion appliances |
| naphthalene | pesticides (moth balls) |
| paradichlorobenzene | pesticides (moth crystals); toilet bowl deodoriser; room deodorisers |
| chloroform | pesticides; showering; washing clothes and dishes |
| acetaldehyde | tobacco smoke; water-based paint; unvented combustion appliances; leakage from wood stoves, furnaces, and fireplaces; (outdoor air also an important source) |
| benzene | tobacco smoke; some furnishings, paints, coatings, wood products, from stored gasoline or vehicle operation or evaporation from hot engines in attached garages (outdoor air also an important and often predominant source) |
The importance of eliminating tobacco smoke indoors cannot be stressed enough. Environmental tobacco smoke (ETS) is a dynamic, complex mixture of more than 4,000 chemicals, many known toxic or carcinogenic agents. The ubiquitous nature of ETS in indoor environments indicates that some unintentional inhalation of ETS by non-smokers is unavoidable. EPA estimates that ETS is responsible for some 3,000 lung cancer deaths per year among non-smokers in the US. The US Surgeon General, the National Research Council, and the National Institute for Occupational Safety and Health also concluded that passive smoking can cause lung cancer in otherwise healthy adults who never smoked. Children's lungs are even more susceptible to harmful effects from ETS. There is also strong evidence of increased middle ear effusion, reduced lung function, and reduced lung growth.
Given the risks to our health, we should definitely pay more heed to our indoor air quality.
