A method and system for estimating one, two or more unknown components in
a gas. A first array of spaced apart carbon nanotubes ("CNTs") is
connected to a variable pulse voltage source at a first end of at least
one of the CNTs. A second end of the at least one CNT is provided with a
relatively sharp tip and is located at a distance within a selected range
of a constant voltage plate. A sequence of voltage pulses
{V(t.sub.n)}.sub.n at times t=t.sub.n (n=1, . . . , N1; N1.gtoreq.3) is
applied to the at least one CNT, and a pulse discharge breakdown
threshold voltage is estimated for one or more gas components, from an
analysis of a curve I(t.sub.n) for current or a curve e(t.sub.n) for
electric charge transported from the at least one CNT to the constant
voltage plate. Each estimated pulse discharge breakdown threshold voltage
is compared with known threshold voltages for candidate gas components to
estimate whether at least one candidate gas component is present in the
gas. The procedure can be repeated at higher pulse voltages to estimate a
pulse discharge breakdown threshold voltage for a second component
present in the gas.