Respiratory disease is prevalent in New Zealand. Unfortunately, New Zealand has an extremely high incidence of respiratory-related diseases, such as asthma, lung cancer, pneumonia, bronchitis, and rheumatic fever. There are three main aspect of housing: damp houses, overcrowding, and indoor secondhand smoking.

First, a warm, comfortable and ventilated housing is beneficial for humans’ health and wellbeing while, non-ventilated housing can cause a variety of health issues. According to Public Health Agency (2013), asthma may aggravate in cold, damp houses. Regional Public Health (2012) states that damp rooms cause dust mites to increase, which exacerbate asthma. Additionally, dampness or moisture encourages mould growth. Consequently, mould can irritate the airways of the lungs (Regional Public Health, 2012). This issue of cold and damp houses may be due to a leakage, inadequate ventilation and ageing of the house. According to Douwes (2009), the increased chemical emissions from building materials and floor covers may be due to the excess moisture. Moreover, inadequate ventilation is one of the causes of dampness; other potential harmful indoor pollutants may increase due to poor ventilation (Douwes, 2009). Likewise, insulation in the damp house may be difficult. According to Auckland Regional Public Health Service (2004), the microorganism was likely to increase in a favourable environment due to the increase of condensation indoors from cold air. According to Regional Public Health (2012), around 30 percent of New Zealand homes have no insulation and 73 percent of rental homes have some mould. Additionally, the standard of living may be associated with the housing issue (e.g. damp and cold houses). According to Statistics New Zealand (2013), people experience severe material hardship were more likely to report a major housing problem as shown in New Zealand General Social Survey in 2010/2011. The figures illustrate that 32 percent of people (36,000) and 45 percent of people (51,000) live in damp and cold houses, respectively. In addition, people who experience a significant material standard of living that said they had cold housing where those people in sole-parent families which is around 70,000 people. Likewise, renters were more likely to report an experience of cold and damp housing than owner-occupiers that were 25 percent, or 275, 000 people (Statistics New Zealand, 2013). There may be more people in New Zealand with lower income that may find it difficult to have an own house. According to Chapman et al. (2012), the landlord in a private rental market in New Zealand does not provide heating and retrofit insulation for tenants. Consequently, tenants who may not occupy for long periods are unlikely to invest in improving homes and without the landlord consent tenants cannot change the fabric of the building. However, a scheme was updated on 2007, which provided subsidies and grants for retrofitted insulation to low-income households and Interest-free loans for some appliances. Additionally, landlords received a partial subsidy scheme to improve rental accommodation energy efficiency (Chapman et al., 2012). There is a prevalent issue regarding cold and damp houses in New Zealand.However, it is clear that the government found the necessity of improving the health and welfare in the residential sector through offering subsidies in housing insulation.

Apart from cold and damp housing that affects human health, mainly respiratory related disease, is overcrowding. According to Ministry of Health (2014), respiratory infections including pneumonia and rheumatic fever are some of the health conditions associated with household crowding. According to Auckland Regional Public Health Service (2004), crowding has no objective measure. However, crowding may be identified by the number of residents divided by the number of rooms, which exceeds the capacity of the household. The statistics New Zealand 2003 report uses the Canadian National Occupany Standard which assumes that no more than two individual per room, however, the use of the lounge for sleeping can be counted as crowding. Moreover, individuals who live in crowded dwellings have poorer physical and mental health than people in uncrowded housing. People are at higher risk in overcrowded homes because the space is restricted and would be difficult to avoid disease or illness. Other crowding-related conditions are bronchiectasis (damage in airways of the lung causing a permanent widening leading to serious lung infections) and rheumatic fever (develops after throat infection). Moreover, less affordable housing for people on low incomes encourages crowded housing. The overwhelming stress of living in an overcrowded environment makes the dwellers have the lack of emotional strength to move out of the situation. In addition, overstayers or illegal immigrants that live in crowded households are usually cautious about informing the officials about their living arrangements. Correspondingly, crowded households encourage unhygienic conditions. This unhygienic concern may lead individuals to not inform the official of their current living arrangement because it may hinder their benefits or removal of their children. Furthermore, the population facing the most crowding is Pacific people. In 2001, 41 percent of Pacific people living in household needing at least two extra bedrooms. Likewise, Pacific people most likely to be undercounted than Pakeha who is most likely to be counted in official statistics about crowding. In 2001, the highest proportion of Maori and Pacific's households defined as crowded was in Manukau City. In addition, the highest proportion of overcrowding within Asian households is located. The Healthy Housing Programme supplied insulation ventilation, health information, and in some extra rooms to houses in Otara, Onehunga and Mangere from 2001 to 2002. The purpose of this is to reduce crowding in houses by extending houses, building larger houses, and rehousing families in more suitably-sized accommodation (Auckland Regional Public Health Service, 2004). Moreover, New Zealand Government announces more support for Maori housing. According to Social Housing Unit (2014), the Maori Housing Unit will be established that may improve housing for Maori, who are affected by overcrowding. A housing project was implemented at Weymouth where large-scale affordable housing is being built (Collins, 2014).

Apart from cold, damp and overcrowding homes, the last, but not the least concern for a respiratory related disease is indoor secondhand smoking. According to Smokefree Organization (2009), secondhand hand smoking is poisonous and causes disease and worse deaths in adults and children. According to statistics New Zealand (2014), 13 people die daily from smoking or secondhand-smoking. It is found that second-hand smoking has at least 250 chemicals that cause cancer (e.g. lung cancer) and can worsen asthma attacks. Unfortunately, individuals inhaling the smoke released from the cigarette are more highly concentrated with toxins than the smoke breathed out by a smoker. Reducing exposure to secondhand smoking is a public health priority. According to Ministry of Health (2014), New Zealand has three key objectives of tobacco control activities. The objectives are reduce exposure to second-hand smoke, increase quitting for smokers, and reduce smoking initiation. In March 2011 the Government adopted the Smokefree 2025 goal for New Zealand (Ministry of Health, 2014).

To conclude, it is clear that the three indoor environmental factors affects human health mainly the pulmonary areas of the body. These complications are mainly asthma, rheumatic fever, brionchiectasis, and lung cancer. Despite this, it has been proven that certain actions both from the individuals in a soceity and the government are needed to prevent the harmful effects of damp or cold homes, excess number of residents in a household, and passive smoking or secondhand smoking.

References
Auckland Regional Public Health Service (2004). Housing and Health. Retrieved April 21, 2015, from http://www.arphs.govt.nz/
Chapman, P. H., Viggers, H., Chapman, R., O’Sullivan, K., Barnard, L. T., & Lloyd, B. (2012). Tackling cold housing and fuel poverty in New Zealand: A review of policies, research, and health impacts. Energy Policy, 49, 134-142. doi:10.1016/j.enpol.2011.09.044
Collins, S. (2014, February 4). Building a new future: Bold new vision for affordable housing. The New Zealand Herald, pp. 1.
Douwes (2009). Building dampness and its effect on indoor exposure to biological and non-biological pollutants. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK143941/pdf/TOC.pdf
Ministry of Health (2014). Infectious Diseases Attributable to Household Crowding in New Zealand: A systematic review and burden of disease estimate. Retrieved April 21, 2015, from www.health.govt.nz/
Smokefree Organization (2009). Secondhand smoking. Retrieved April 21, 2015, from http://smokefree.org.nz/
Statistics New Zealand (2014). Tobacco smoking. Retrieved April 21, 2015, from http://www.stats.govt.nz/