Page 222 - Advances In Productive, Safe, and Responsible Coal Mining

Diesel particulate matter: Monitoring and control improves safety and air quality 201

the transport of aerosols and ultimately on the health endpoints associated with
exposure. This is primarily because the deposition efficiency of the particle in the
respiratory tract depends upon particle size [28–31]. Coarse-mode aerosols are mainly
deposited in the anterior nose and extrathoracic regions of the human respiratory tract.
Due to the small particle size, diesel aerosols are mainly deposited in bronchial,
bronchiolar, and alveolar regions of the human respiratory tract. The nucleation
and accumulation-mode diesel aerosols readily penetrate into the alveolar regions
where gas exchange occurs [31].
A harmful aspect of the use of diesel as a fuel is its resultant emissions as an adverse
environmental agent. DPM is a major cause of a large number of occupational diseases
[32]. Diesel emissions contain various respiratory irritants in both the gas and partic-
ulate phases and can cause various acute effects. Published studies [33–35] report the
severe effects of DPM exposure in which particular concern is the reported chronic
health effects of DPM exposure. Diesel particles are very small in size and generally
less than a micron [18]. Because of their small size, DPM particles penetrate deep into
the human lungs [17]. Long-term and continuous exposure to DPM can result in severe
health issues, which include respiratory diseases, lung cancer, reduced lung capacity,
pneumonia, and heart disease [26,33,34,36]. In occupational settings, human epide-
miological studies have demonstrated an association between increased lung cancer
rate and diesel exhaust exposure [37–39]. The National Institute of Occupational
Safety and Health (NIOSH) regards diesel exhaust as a “potential carcinogen,” and
states that reductions in workplace DPM exposure reduces cancer risks [33]. The
International Agency for Research on Cancer (IARC) has declared that “diesel engine
exhaust is carcinogenic to humans” [40]. A reported study suggests that the risk of
lung cancer among workers that are heavily exposed to respirable EC (between
3
640 and 1280μg/m ) was five times more than the risk in the lowest exposure category
3
(<20μg/m ) [38]. In addition, acute exposure to diesel exhaust can also cause dele-
terious health effects like eye and nose irritation, headaches, nausea, lightheadedness,
vomiting, numbness, and asthma [41,42]. Other diesel exhaust exposure effects
include bronchial irritation, cough, phlegm, and neurophysiologic symptoms [43].

11.4 Regulatory impact on underground mines diesel
equipment

MSHA regulates the usage of diesel equipment in US underground mines. MSHA ini-
tiated rulemaking regarding DPM in order to reduce the DPM exposure of under-
ground miners. Based on mining commodities, MSHA has divided the mining
industry into two separate sections for regulation purposes: (a) coal mines and
(b) metal-nonmetal (M/NM) mines.

11.4.1 Impact on underground coal mines

In underground coal mines, MSHA imposes distinct requirements for diesel-powered
equipment usage. This is due to the possible presence of coal dust, explosive gas
mixtures, and other related safety matters. MSHA also requires that any diesel