The occurrence of asthma and allergy is rapidly increasing in children. There is a lot of research and literature linking ambient air pollution and asthma morbidity but less is known about the impact of indoor air pollution. The indoor environment is really important to look at when we are studying children since they often spend a large portion of the day indoors.
Asthma is one of the most common chronic diseases in children worldwide , with a widespread prevalence varying from around 1% to more than 30% across the world . The prevalence of asthma in Hong Kong among 13 – 14 years old school children was 9.1% in 1994 – 95 and rose to 9.4% in 2002 – 03. Children in Stockholm were more recently investigated by a prospective birth cohort study (BAMSE), which reported a prevalence of around 6–7% .
The long-term goal of asthma management is to control the child’s symptoms, diminish the risk of future exacerbations and ensure that the child can cope with his or her daily activities1. Children and adolescents with asthma often feel unhealthy or feel that they do not have the same opportunities as their peers when it comes to physical activities.Many aspects of their lives are affected. As well as suffering symptoms, and being limited in their physical activities, they also suffer from the fear of having an asthma attack, and some children are bullied.
Several factors affect the development of asthma. Early exposure to fine particulate matter (PM2.5) has been shown to reduce lung function at eight years of age and increase the risk for pneumonia before the age of two . The Swedish BAMSE study including more than 4000 children presents data indicating that exposure to air pollution from heavy traffic during the first year increases the risk for chronic asthma and sensitization to pollen at the age of four .
It is well accepted that high vehicle traffic is associated with asthma, cough, and wheeze in children with known allergic sensitization . However, the indoor air quality is even more important as children spend 90% of their time indoors . Apart from fine and ultra-fine particles generated both indoors and outdoors, there is also the risk for aggravating viral infections mould exposure .
Global Initiative for Asthma (GINA). Global strategy for asthma management and prevention. 2014. Available from: http://www.ginasthma.org/local/uploads/files/GINA_Report_2014.pdf
Asher MI, Montefort S, Björksten B et al. Worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: ISAAC Phases One and Three repeat multicounty cross-sectional surveys. Lancet 2006; 368: 733–43.
Ballardini N, Kull I, Lind T, Hallner E, Almqvist C, Ostblom E, et al. Development and comorbidity of eczema, asthma and rhinitis to age 12 – data from the BAMSE birth cohort. Allergy 2012; 67: 537–44.
Wildhaber J, Carrol WD, Brand PLP. Global Impact of Asthma on Children and Adolescents’ Daily Lives: the Room to Breathe Survey. Pediatr Pulmonol 2012; 47: 346–57.
Schultz ES, Gruzieva O, Bellander T, Bottai M, Hallberg J, Kull I, Svartengren M, Melén E, Pershagen G. Traffic-related air pollution and lung function in children at 8 years of age: a birth cohort study. Am J Respir Crit Care Med. 2012 Dec 15;186(12):1286-91.
MacIntyre EA, Gehring U, Mölter A et al. Air pollution and respiratory infections during early childhood: an analysis of 10 European birth cohorts within the ESCAPE Project. Environ Health Perspect. 2014 Jan;122(1):107-13.
Nordling E, Berglind N, Melén E,. Traffic-related air pollution and childhood respiratory symptoms, function and allergies. Epidemiology. 2008 May;19(3):401-8.
Pekkanen J, Timonen KL, Ruuskanen J, Reponen A, Mirme A. Effects of ultrafine and fine particles in urban air on peak expiratory flow among children with asthmatic symptoms. Environ Res 1997; 74: 24–33.
Hirsch T, Weiland SK, von Mutius E, et al. Inner city air pollution and respiratory health and atopy in children. Eur Respir J 1999; 14: 669–677.
Breysse P N, Diette G B, Matsui E C et al. Indoor Air Pollution and Asthma in Children. Proc Am Thorac Soc Vol 7. 102–106, 2010.
Sears M R, Epidemiology of asthma exacerbations. J Allergy Clin Immunol 2008;122:662-8.
Antova T, Pattenden S, Brunekreef B et al. Exposure to indoor mould and children’s respiratory health in the PATY study. J Epidemiol Community Health 2008;62:708–714.