Air pollution – once considered an insidious health risk of the big city outdoors – is now creeping into indoor workplaces. At least that is the initial conclusion of case studies in Thessaloniki. Measurements taken by Aristotle University in Thessaloniki – and presented last weekend at a conference in the northern port – show that some indoor workplaces are registering levels of dangerous pollutants that are more than twice the limit decreed for outdoor spaces. If smokers light up in indoor workplaces the already high levels increase even more. «Smoking especially increases the levels of pollution in the atmosphere of indoor workplaces,» said Constantina Samara, a professor at Aristotle University’s chemistry department who participated in the pollution measurements. She said toxic elements in work environments where smoking was permitted increased between 50 and 70 percent. Pollutants in indoor spaces often originate from the activities that go on inside the building. However, pollution from outdoors can also enter the indoor area. Air pollution is measured in micrograms per cubic meters of air. Limits for air quality standards encompass pollutants such as sulfur dioxide, carbon monoxide, ozone and particulate matter – tiny clumps of soot, dirt and various chemicals that have been linked to health problems such as asthma and other diseases of the cardiovascular system or lungs. Environmental scientists group particulate matter – called PM – into two categories – coarse particles and fine particles. Coarse particles are between 2.5 and 10 micrometers in diameter, or about 25 to 100 times thinner than a human hair, according to US government data. Formed through the crushing and grinding of rocks and soil and circulated in the air by the wind, this matter includes smoke and factory dirt and dust. Coarse particles cause less severe health problems. Of more concern are fine particles, which are smaller than 2.5 micrometers in diameter and are 100 times thinner than a human hair. These fine particles – which include toxic organic compounds and heavy metals such as cadmium, lead, arsenic and zinc – are created through the likes of automobile exhaust and smelting. These particles cause more health damage because they penetrate deep into the lungs. Physical effects include respiratory illnesses, aggravated asthma, chronic bronchitis and decreased lung function. Scientists say those most at risk from fine particles include the elderly, individuals with a pre-existing heart or lung disease, children and asthmatics. The Aristotle University data showed that in indoor workplaces with no smokers, measurements showed 94 micrograms of 10 PM particles per cubic meter of air and 70 micrograms of the more dangerous 2.5 PM particles per cubic meter of air. In areas with smokers, the measurements showed significantly higher levels: 141 micrograms of 10 PM per cubic meter of air and 118 micrograms of 2.5 PM per cubic meter of air. Smokers pollute Governments in Greece and many other countries have not yet set air pollution limits to control health risks in indoor spaces. That’s probably because few official measurements have been conducted showing the percentage of especially dangerous particles in indoor spaces. Outdoors, the base level of PM 10 particles has increased 100-fold; it cannot go above 50 micrograms per cubic meter of air. No upper limits have yet been set for the finer and more dangerous PM 2.5 particles, since dirt and soot have just recently begun being measured. Samara and her colleagues at Aristotle University measured pollution in indoor spaces for an initial study presented at an environmental conference which ended last Tuesday. The scientists are continuing their work. «During the 1960s, there was this view that we should get indoors to escape pollution,» Samara said. «But the pollutants trapped indoors have a much lower chance of scattering than those in the open air.» Samara said air pollution levels in indoor work spaces in Athens are likely much higher than those measured in Thessaloniki. She also said polluting microparticles are at noticeably lower levels on a building’s upper floors. In the Aristotle University study, much lower levels of the pollutants were found on the sixth through the ninth floors. The measurements also show that the concentration of pollutants is also dependent on the size of the indoor workplace and the number of people who spend many hours there. Add smokers to the mix, and the pollution levels peak. Workers in those spaces can do a few things to help decrease coarse and fine PM levels. Air conditioners can help, if their filters are cleaned diligently. So can ionizers, which cause particles to scatter, and proper ventilation. But scientists say the best solution is decreasing the levels of outdoor pollution, especially that emitted by automobiles, which are responsible for creating the most dangerous particulate matter.